Aerial view of the mushroom cloud of smoke as it billows 20,000 ft. in the air, following the United States Air Force's detonation of an atomic bomb over the city of Hiroshima, Japan, August 6, 1945. (Photo by Time Life Pictures/US Army Air Force/The LIFE Picture Collection/Getty Images)

Aerial view of the mushroom cloud of smoke as it billows 20,000 ft. in the air, following the United States Air Force's detonation of an atomic bomb over the city of Hiroshima, Japan, August 6, 1945. (Photo by

Aerial view of the mushroom cloud of smoke as it billows 20,000... Photo-13640940.159606 - seattlepi.com

Image 2 of 98

"At 8:16 a.m. on 6 August 1945, above Hiroshima, Japan, Captain William Parsons of the United States Navy, armed and released 'Little Boy' from the bomb bay of the B-29 Superfortress, Enola Gay. When the bomb was loaded on the plane, it was accompanied by this hand receipt. The receipt shows the chain of responsibility from Dr. Norman Ramsey, the lead scientist of the bomb's construction team, to Brigadier General Thomas Farrell, field operations commander of Tinian Island Air Strip, and lastly, Captain Parsons, mission commander. The note on the side of the receipt is from Parsons acknowledging he 'expended'the weapon. The signatures of Manhattan and Alberta Project personnel were collected by BG Farrell after the Enola Gay returned from its mission." -- U.S. Army Heritage and Education Center

"At 8:16 a.m. on 6 August 1945, above Hiroshima, Japan, Captain William Parsons of the United States Navy, armed and released 'Little Boy' from the bomb bay of the B-29 Superfortress, Enola Gay. When the bomb

6th September 1945: Hiroshima one month after the atomic bomb was dropped. In the background is the dome of the Hiroshima Observatory which survived the explosion and remains as a shrine to the event. (Photo by Hulton Archive/Getty Images)

6th September 1945: Hiroshima one month after the atomic bomb was dropped. In the background is the dome of the Hiroshima Observatory which survived the explosion and remains as a shrine to the event. (Photo

A scene from the film 'Hiroshima', funded by the Japanese School Teacher's Union to highlights the devastation of the atomic bomb at the end of World War Two, Japan, 1952. (Photo by European/FPG/Getty Images)

A scene from the film 'Hiroshima', funded by the Japanese School Teacher's Union to highlights the devastation of the atomic bomb at the end of World War Two, Japan, 1952. (Photo by European/FPG/Getty Images)

Photo: FPG/Getty Images

A scene from the film 'Hiroshima', funded by the... Photo-13640959.159606 - seattlepi.com

Image 23 of 98

Devastation at Hiroshima, after the atomic bomb was dropped. The building on the right was preserved as the Hiroshima Peace Memorial, Atomic Bomb Dome or Genbaku Dome.(Photo by Keystone/Getty Images)

Devastation at Hiroshima, after the atomic bomb was dropped. The building on the right was preserved as the Hiroshima Peace Memorial, Atomic Bomb Dome or Genbaku Dome.(Photo by Keystone/Getty Images)

Photo: Keystone/Getty Images

Devastation at Hiroshima, after the atomic bomb was dropped. The... Photo-13640957.159606 - seattlepi.com

Image 24 of 98

Victims of the atomic blast sit in a makeshift hospital in a damaged bank building in the centre of Hiroshima. (Photo by Keystone/Getty Images)

Victims of the atomic blast sit in a makeshift hospital in a damaged bank building in the centre of Hiroshima. (Photo by Keystone/Getty Images)

Photo: Keystone/Getty Images

Victims of the atomic blast sit in a makeshift hospital in a... Photo-13640956.159606 - seattlepi.com

Image 25 of 98

Taboola Gallery Frame Item-85307.159606 - seattlepi.com

Image 26 of 98

circa 1945: The ruins of Hiroshima after the bombing. (Photo by MPI/Getty Images)

circa 1945: The ruins of Hiroshima after the bombing. (Photo by MPI/Getty Images)

Gutted trolley car amid Hiroshima ruins a few months after the dropping of the atomic bomb by the US, bringing a swift Japanese surrender and an end to WWII. (Photo by Bernard Hoffman/The LIFE Picture Collection/Getty Images)

Flattened neighborhood blgs. reduced to complete rubble by atomic bomb blast a few mos. after the US attack that ushered in an end to WWII. (Photo by Bernard Hoffman/The LIFE Picture Collection/Getty Images)

Flattened neighborhood blgs. reduced to complete rubble by atomic bomb blast a few mos. after the US attack that ushered in an end to WWII. (Photo by Bernard Hoffman/The LIFE Picture Collection/Getty Images)

A man in hospital shows the keloids on his back caused in the wake of the atomic explosion in Hiroshima, Japan, August 1947. (Photo by Carl Mydans/The LIFE Picture Collection/Getty Images)

A man in hospital shows the keloids on his back caused in the wake of the atomic explosion in Hiroshima, Japan, August 1947. (Photo by Carl Mydans/The LIFE Picture Collection/Getty Images)

Photo: Carl Mydans/The LIFE Picture Collection/Getty Images

A man in hospital shows the keloids on his back caused in the wake... Photo-13640943.159606 - seattlepi.com

Image 32 of 98

August 1945: A man wheels his bicycle thorough Hiroshima, days after the city was leveled by an atomic bomb blast, Japan. The view here is looking west-northwest, about 550 feet from where the bomb landed, known as X, on August 6, 1945. (Photo by Keystone/Getty Images)

August 1945: A man wheels his bicycle thorough Hiroshima, days after the city was leveled by an atomic bomb blast, Japan. The view here is looking west-northwest, about 550 feet from where the bomb landed,

Burned out buses amidst the flattened neighborhood blgs. which are reduced to complete rubble by atomic bomb blast a few mos. after the US attack that ushered in an end to WWII. (Photo by Bernard Hoffman/The LIFE Picture Collection/Getty Images)

Burned out buses amidst the flattened neighborhood blgs. which are reduced to complete rubble by atomic bomb blast a few mos. after the US attack that ushered in an end to WWII. (Photo by Bernard Hoffman/The

Yoshinori Sakai, who was born in Hiroshima on the day the first atomic bomb devastated the city, lights the Olympic flame in Tokyo's main stadium during the opening of the Olympic Games, 10th October 1964. (Photo by Ishi/Keystone/Hulton Archive/Getty Images)

Yoshinori Sakai, who was born in Hiroshima on the day the first atomic bomb devastated the city, lights the Olympic flame in Tokyo's main stadium during the opening of the Olympic Games, 10th October 1964.

Yoshinori Sakai, who was born in Hiroshima on the day the first... Photo-13640930.159606 - seattlepi.com

Image 38 of 98

Residents wander cleaned up streets amid ruins of buildings reduced to piles of rubble by the atomic bomb dropped a few months earlier by the US which brought about a swift end to the war. (Photo by Bernard Hoffman/The LIFE Picture Collection/Getty Images)

Residents wander cleaned up streets amid ruins of buildings reduced to piles of rubble by the atomic bomb dropped a few months earlier by the US which brought about a swift end to the war. (Photo by Bernard

HIROSHIMA, JAPAN: This September 1945 file picture shows the remaining of the Hiroshima Prefectural Industry Promotion Building, known as the Atomic-Bomb Dome, which was later preserved as a monument. (Photo credit should read AFP/Getty Images)

HIROSHIMA, JAPAN: This September 1945 file picture shows the remaining of the Hiroshima Prefectural Industry Promotion Building, known as the Atomic-Bomb Dome, which was later preserved as a monument. (Photo

7th August 1945: Aerial view of Hiroshima the day after the United States dropped the atomic bomb on it during World War II, Japan. (Photo by Hulton Archive/Getty Images)

7th August 1945: Aerial view of Hiroshima the day after the United States dropped the atomic bomb on it during World War II, Japan. (Photo by Hulton Archive/Getty Images)

Photo: Hulton Archive/Getty Images

7th August 1945: Aerial view of Hiroshima the day after the... Photo-13640925.159606 - seattlepi.com

Image 44 of 98

US and Japanese civilians work to rebuild the homes lost in the atomic bomb in Hiroshima following World War Two, with the 'Houses for Hiroshima' Work Camp Project, Japan, 1950. (Photo by European/FPG/Getty Images)

US and Japanese civilians work to rebuild the homes lost in the atomic bomb in Hiroshima following World War Two, with the 'Houses for Hiroshima' Work Camp Project, Japan, 1950. (Photo by European/FPG/Getty

US and Japanese civilians work to rebuild the homes lost in the... Photo-13640920.159606 - seattlepi.com

Image 45 of 98

Taboola Gallery Frame Item-85307.159606 - seattlepi.com

Image 46 of 98

HIROSHIMA, JAPAN - JANUARY 1: Picture dated 1948 showing the devastated city of Hiroshima after the US nuclear bombing on the city 06 August 1946 during World War II. (Photo credit should read STF/AFP/Getty Images)

HIROSHIMA, JAPAN - JANUARY 1: Picture dated 1948 showing the devastated city of Hiroshima after the US nuclear bombing on the city 06 August 1946 during World War II. (Photo credit should read STF/AFP/Getty

JAPAN - SEPTEMBER 1945: Homeless group of mostly children warm their hands over a fire on the outskirts of Hiroshima after the end of WWII. (Photo by Alfred Eisenstaedt/Pix Inc./The LIFE Picture Collection/Getty Images)

JAPAN - SEPTEMBER 1945: Homeless group of mostly children warm... Photo-13640854.159606 - seattlepi.com

Image 58 of 98

JAPAN - AUGUST 01: Some Victims Of The Catastrophe Who Took Refugee In The Rubbles Of A Bank, Transformed Into A Provisonal Haven. On August 01St 1945. (Photo by Keystone-France/Gamma-Keystone via Getty Images)

JAPAN - AUGUST 01: Some Victims Of The Catastrophe Who Took Refugee In The Rubbles Of A Bank, Transformed Into A Provisonal Haven. On August 01St 1945. (Photo by Keystone-France/Gamma-Keystone via Getty

JAPAN - AUGUST 01: Some Victims Of The Catastrophe Who Took... Photo-13640852.159606 - seattlepi.com

Image 59 of 98

An unidentified man (who appears to be in a US military uniform) stands amid rubble and looks at the ruins of the Hiroshima Prefectural Industrial Promotion Hall, following the US atomic bombing of Hiroshima, Japan, late 1945. The structure was preserved and was later renamed the Genbaku Domu (or Hiroshima Peace Memorial). (Photo by Bernard Hoffman/The LIFE Picture Collection/Getty Images)

An unidentified man (who appears to be in a US military uniform) stands amid rubble and looks at the ruins of the Hiroshima Prefectural Industrial Promotion Hall, following the US atomic bombing of Hiroshima,

August 1946: A view of Hiroshima one year after being the target for the first atomic bomb. It was estimated that between six and ten thousand corpses still lay under the ruins of the city that was sixty per cent destroyed by the atomic blast. (Photo by Keystone/Getty Images)

August 1946: A view of Hiroshima one year after being the target for the first atomic bomb. It was estimated that between six and ten thousand corpses still lay under the ruins of the city that was sixty per